Optical recording medium, optical recording medium production method, optical recording medium production apparatus, program, and medium

ABSTRACT

There are some cases that an accuracy is low for reading unique information identifying an individual from an optical disk which comprises a plurality of information layers.  
     The optical disk according to the present invention is an optical disk which comprises a first information layer  102  and a second information layer  104  for holding information so that by means of incident light, (1) the information will be reproduced or (2) the information will be recorded and reproduced, and which comprises a BCA area which is formed in the first information layer  102  and in which individual identification information  106  uniquely given to the optical disk is recorded.

FIELD OF THE INVENTION

[0001] The present invention relates to an optical recording medium, amethod of manufacturing optical recording medium, an apparatus ofmanufacturing optical recording medium, a program, and a medium.

BACKGROUND OF THE INVENTION

[0002] Over the recent years, as the volume of information required byaudio/video equipment has increased, an increased attention has beenpaid to disk-shaped optical recording mediums, or so-called opticaldisks, which allow an easy access to data, storage of a large volume ofdata and superiority in reduction of the sizes of equipment. Opticaldisks include reproduction-only optical disks, write-once-read-manyoptical disks, phase-change type optical disks and magnetic opticaldisks as read-write optical disks, etc., which are called CDs, DVDs, MOsand the like and used in a variety of actual applications. Aninformation layer in such an optical disk, if the disk is areproduction-only optical disk for instance, is comprised of a syntheticresin substrate, in which convex and concave pit arrays are formed in aspiral arrangement in accordance with recorded information, and a metalthin film of gold, aluminum or other substance which covers the pitarrays on the synthetic resin substrate and serves as a reflection filmfor reproduction laser light.

[0003] Meanwhile, as structure elements of the information layer, awrite-once-read-many optical disk or rewritable optical disk comprises asynthetic resin substrate in which a tracking groove pattern is mainlyrecorded, a recording film such as a dye recording film and aphase-change recording film, and further, in accordance with necessity,a reflection film which reflects reproduction laser light. As therecording film, a thin film which assumes two states that can bedetected by means of laser irradiation is used. Information isreproduced, as convex and concave pits formed on a synthetic resinsubstrate in the case of a reproduction-only optical disk, but marksformed in a recording film on grooves in the case of awrite-once-read-many optical disk or rewritable optical disk, reflectreproduction laser light, and as whether there are pits or marks, thelength of a pit or mark and the interval between pits or marks aredetermined from changes in intensity of the reflection light.

[0004] These synthetic resin substrates are manufactured by injectionmolding of a synthetic resin such as polycarbonate, using a metallicmolding board of Ni in general which includes a convex and concave pitpattern or groove pattern and is referred to as “a stamper.” Aninjection molding method permits to quickly manufacture a large numberof synthetic resin substrates which contain the same information, usingthe same stamper. However, since thus manufactured synthetic resinsubstrates were all transferred from the same stamper, the pit or groovepattern remains entirely identical and so does the information.

[0005] This necessitates identification information unique to anindividual, for managing optical disks. This is for the purpose ofprevention of unauthorized copying is aimed at from a perspective ofcopyright protection, for example. Such identification information isdifferent between individual mediums, and hence, can not be createdusing an injection molding method mentioned above. In addition, it mustbe ensured that the information can not be rewritten with ordinaryoptical disk recording/reproducing apparatuses which are generallyavailable in the market. Noting this, proposals have been made regardingtechniques for recording unique identification information which isdifferent among individuals by a different method other than aninjection molding method.

[0006] As a method of additionally recording information on a DVD, thereis a standard with respect to recording of additional information in aform which resembles a barcode which is an aggregation of diametricalparallel lines. This recording standard stipulates standardizedrecording areas, modulation scheme, error correction scheme, etc.

[0007] This method, for a DVD-ROM for instance, requires to irradiatelaser light upon an information layer inside a fabricated optical disk,dissolve and remove a metal thin film which forms the information layer,and define a barcode-like pattern having different reflectioncoefficients between the removed portions and the surroundinginformation layer.

[0008] There is alternatively a method which does not utilizedissolution of the metal thin film but requires to irradiate laser lightupon the substance of the information layer inside the optical disk,change the reflection coefficient by changing a chemical, physical oroptical property, and accordingly record information. An optical disk inwhich a phase-change recording film or a dye recording film is used asthe substance of the information layer for instance corresponds to this.

[0009] In this manner, it is possible to specify the origin of theoptical disk based on the unique information, prohibit illegal copyingof the information, and protect the copyright. Further, as theidentification information, a production lot number, a production dateand the like are written on every disk in some cases, for other purposessuch as production management.

[0010] A conventional optical disk comprises a first reproduction-onlyarea of BCA (Burst Cutting Area, or sometimes information recorded inBCA) or the like, a second dedicated area formed by pre-pits, and a dataarea.

[0011] The first reproduction-only area is for recording uniqueinformation which identifies an individual as described above, whilewritten in the second reproduction-only area is data such as a moldingboard number for the optical disk and an intensity value of optimallaser light for reading data recorded on this optical disk. The secondreproduction-only area is also called “a lead-in area.” If the disk is areproduction-only optical disk, a content is recorded in the data area,but user information is recorded in the data area if the disk is aread-write optical disk.

[0012] However, with the conventional BCA recording method, since BCArecording is executed after a plurality of layers are bonded to eachother, recording takes place over a plurality of mutually stackedinformation layers. This may result in a deteriorated accuracy ofreading the unique information which identifies an individual, or evenin a complete failure of data read in the worst situation. (In the caseof a rewritable optical disk, in some cases, optimization of recordingin each information layer becomes difficult, which in turn obstructsperfect crystallization or exerts an influence such as deformationinduced by excessive heat.)

[0013] In addition, since the area dedicated to BCA recording which islarge but has a small capacity gets occupied when the conventional BCArecording method is used, a read-write area which is originally intendedfor writing of data may shrink and a substantial recording capacity mayaccordingly decrease. For instance, the occupied area described above isas wide as 1.2 mm in a DVD-ROM.

DISCLOSURE OF THE INVENTION

[0014] Considering the problems above with the conventional techniques,the present invention aims at providing an optical recording medium, amethod of manufacturing optical recording medium, an apparatus ofmanufacturing optical recording medium, a program, and a medium, withwhich it is possible to improve an accuracy of reading uniqueinformation which identifies an individual from an optical disk whichcomprises a plurality of information layers.

[0015] In light of the problems above with the conventional techniques,the present invention also aims at providing an optical recordingmedium, a method of manufacturing optical recording medium, an apparatusof manufacturing optical recording medium, a program, and a medium, withwhich it is possible to reduce a dedicated area which is for recordingunique information which identifies an individual.

[0016] The 1st invention of the present invention (corresponding toclaim 1) is an optical recording medium which comprises a plurality ofinformation layers for holding information so that by means of incidentlight, (1) said information will be reproduced or (2) said informationwill be recorded and reproduced,

[0017] comprising a unique identification information recording area inwhich unique identification information uniquely given to said opticalrecording medium is recorded and which is disposed in one of saidplurality of information layers.

[0018] The 2nd invention of the present invention (corresponding toclaim 2) is the optical recording medium of the 1st invention, whereinsaid unique identification information recording area is disposed in theinformation layer among said plurality of information layers which isthe closest to a surface upon which said light is incident.

[0019] The 3rd invention of the present invention (corresponding toclaim 3) is the optical recording medium of the 1st invention, whereinsaid plurality of information layers are formed on predeterminedsubstrates, and

[0020] said unique identification information recording area is disposedin the information layer among said plurality of information layerswhich is formed on the thickest one of said substrates.

[0021] The 4th invention of the present invention (corresponding toclaim 4) is an optical recording medium which comprises a plurality ofinformation layers for holding information so that by means of incidentlight, (1) said information will be reproduced or (2) said informationwill be recorded and reproduced,

[0022] comprising unique identification information recording areas inwhich unique identification information uniquely given to said opticalrecording medium is recorded and which are disposed in two or more ofsaid plurality of information layers so as not to overlap with eachother as viewed from a direction in which said light is incident.

[0023] The 5th invention of the present invention (corresponding toclaim 5) is the optical recording medium of the 1st or 4th invention,wherein said plurality of information layers are formed on a substratewhich has the shape of a disk, and

[0024] said unique identification information is recorded in the form ofstripes which are along the radial direction of said disk.

[0025] The 6th invention of the present invention (corresponding toclaim 6) is the optical recording medium of the 1st or 4th invention,wherein said plurality of information layers are formed mainly by thinfilms which can assume two states which are irreversible and can bedetected when irradiated with a laser.

[0026] The 7th invention of the present invention (corresponding toclaim 7) is the optical recording medium of the 1st or 4th invention,wherein said plurality of information layers are formed mainly by thinfilms which can be dissolved and accordingly removed by irradiation oflight.

[0027] The 8th invention of the present invention (corresponding toclaim 8) is an optical disk which comprises an information layer forholding information so that by means of incident light, (1) informationwill be reproduced or (2) information will be recorded and reproduced,

[0028] comprising a predetermined position information recording area inwhich information regarding a position at which unique identificationinformation, which is given uniquely to said optical disk is recorded,is recorded.

[0029] The 9th invention of the present invention (corresponding toclaim 9) is the optical recording medium of the 8th invention, whereinsaid position information recording area is a BCA area or lead-in areawhich is used for reproduction of said information.

[0030] The 10th invention of the present invention (corresponding toclaim 10) is the optical recording medium of the 8th invention, whereinsaid unique identification information is recorded in a data area inwhich said information is recorded or which is used to record saidinformation.

[0031] The 11th invention of the present invention (corresponding toclaim 11) is the optical recording medium of the 10th invention, whereinsaid unique identification information is recorded so as to have alength which permits error correction during reproduction of saidinformation.

[0032] The 12th invention of the present invention (corresponding toclaim 12) is the optical recording medium of the 10th invention, whereinsaid information layer is formed on a substrate which comprises aplurality of recording tracks and has the shape of a disk,

[0033] wherein said unique identification information is recorded so asto have a width which is not beyond one of said recording tracks.

[0034] The 13th invention of the present invention (corresponding toclaim 13) is an optical recording medium manufacturing method ofmanufacturing an optical recording medium comprising a plurality ofinformation layers for holding information so that by means of incidentlight, (1) said information will be reproduced or (2) said informationwill be recorded and reproduced,

[0035] comprising a step of forming a unique identification informationrecording area in one of said plurality of information layers, andrecording unique identification information, which is given uniquely tosaid optical disk, in said unique identification information recordingarea.

[0036] The 14th invention of the present invention (corresponding toclaim 14) is an optical recording medium manufacturing method ofmanufacturing an optical recording medium comprising a plurality ofinformation layers for holding information so that by means of incidentlight, (1) said information will be reproduced or (2) said informationwill be recorded and reproduced,

[0037] comprising a step of forming unique identification informationrecording areas in two or more of said plurality of information layersso as not to overlap with each other as viewed from a direction in whichsaid light is incident, and recording unique identification information,which is given uniquely to said optical disk, in said uniqueidentification information recording areas.

[0038] The 15th invention of the present invention (corresponding toclaim 15) is an optical recording medium manufacturing method ofmanufacturing an optical recording medium comprising an informationlayer for holding information so that by means of incident light, (1)information will be reproduced or (2) information will be recorded andreproduced,

[0039] comprising:

[0040] a step of recording unique identification information which isgiven uniquely to said optical recording medium; and

[0041] a step of forming a predetermined position information recordingarea and recording, in said position information recording area,information regarding a position at which said unique identificationinformation is recorded.

[0042] The 16th invention of the present invention (corresponding toclaim 16) is the optical recording medium manufacturing method of anyone of the 13th through 15th inventions, wherein said information layeris formed mainly by a phase-change recording film, and

[0043] said unique identification information is recorded utilizing amodulated intensity of laser light which is for initially crystallizingsaid phase-change recording film.

[0044] The 17th invention of the present invention (corresponding toclaim 17) is the optical recording medium manufacturing method of anyone of the 13th through 15th inventions, wherein said information layeris formed mainly by a reflection film against said light which isindecent, and

[0045] said unique identification information is recorded utilizingdissolution and consequent removal of said reflection film.

[0046] The 18th invention of the present invention (corresponding toclaim 18) is an optical recording medium manufacturing apparatus ofmanufacturing an optical recording medium comprising a plurality ofinformation layers for holding information so that by means of incidentlight, (1) said information will be reproduced or (2) said informationwill be recorded and reproduced,

[0047] comprising unique identification information recording meanswhich records unique identification information, which is given uniquelyto said optical recording medium, in a unique identification informationrecording area which is formed in one of said plurality of informationlayers.

[0048] The 19th invention of the present invention (corresponding toclaim 19) is an optical recording medium manufacturing apparatus ofmanufacturing an optical recording medium comprising a plurality ofinformation layers for holding information so that by means of incidentlight, (1) said information will be reproduced or (2) said informationwill be recorded and reproduced,

[0049] comprising unique identification information recording meanswhich records unique identification information, which is given uniquelyto said optical recording medium, in unique identification informationrecording areas which are formed in two or more of said plurality ofinformation layers so as not to overlap with each other as viewed from adirection in which said light is incident.

[0050] The 20th invention of the present invention (corresponding toclaim 20) is an optical recording medium manufacturing apparatus ofmanufacturing an optical recording medium comprising an informationlayer for holding information so that by means of incident light, (1)said information will be reproduced or (2) said information will berecorded and reproduced,

[0051] comprising:

[0052] unique identification information recording means which recordsunique identification information which is given uniquely to saidoptical recording medium; and

[0053] position information recording means which records, in apredetermined position information recording area, information regardinga position at which said unique identification information is recorded.

[0054] The 21st invention of the present invention (corresponding toclaim 21) is the optical recording medium manufacturing apparatus of anyone of the 18th through 20th inventions, wherein said information layersare formed on a substrate which comprises a plurality of recordingtracks and has the shape of a disk, and

[0055] said unique identification information recording means recordssaid unique identification information, utilizing tracking servo oversaid tracking tracks.

[0056] The 22nd invention of the present invention (corresponding toclaim 22) is a program which makes a computer execute the step in theoptical recording medium manufacturing method of the 13th invention offorming said unique identification information recording area in one ofsaid plurality of information layers and recording said uniqueidentification information in said unique identification informationrecording area.

[0057] The 23rd invention of the present invention (corresponding toclaim 23) is a medium which can be processed on a computer and holds aprogram which makes a computer execute the step in the optical recordingmedium manufacturing method of the 13th invention of forming said uniqueidentification information recording area in one of said plurality ofinformation layers and recording said unique identification informationin said unique identification information recording area.

[0058] The 24th invention of the present invention (corresponding toclaim 24) is a program which makes a computer execute the step in theoptical recording medium manufacturing method of the 14th invention offorming said unique identification information recording areas in two ormore of said plurality of information layers so as not to overlap witheach other as viewed from the direction in which said light is incident,and recording said unique identification information, which is givenuniquely to said optical disk, in said unique identification informationrecording areas.

[0059] The 25th invention of the present invention (corresponding toclaim 25) is a medium which can be processed on a computer and holds aprogram which makes a computer execute the step in the optical recordingmedium manufacturing method of the 14th invention of forming said uniqueidentification information recording areas in two or more of saidplurality of information layers so as not to overlap with each other asviewed from the direction in which said light is incident, and recordingsaid unique identification information, which is given uniquely to saidoptical disk, in said unique identification information recording areas.

[0060] The 26th invention of the present invention (corresponding toclaim 26) is a program which makes a computer execute all or some of thestep in the optical recording medium manufacturing method of the 15thinvention of recording said unique identification information which isgiven uniquely to said optical recording medium, and the step in theoptical recording medium manufacturing method of the 15th invention offorming said predetermined position information recording area andrecording, in said position information recording area, the informationregarding the position at which said unique identification informationis recorded.

[0061] The 27th invention of the present invention (corresponding toclaim 27) is a medium which can be processed on a computer and holds aprogram which makes a computer execute all or some of the step in theoptical recording medium manufacturing method of the 15th invention ofrecording said unique identification information which is given uniquelyto said optical recording medium, and the step in the optical recordingmedium manufacturing method of the 15th invention of forming saidpredetermined position information recording area and recording, in saidposition information recording area, the information regarding theposition at which said unique identification information is recorded.

BRIEF DESCRIPTION OF THE DRAWINGS

[0062]FIG. 1 is a cross sectional view of an optical recording mediumaccording to a first preferred embodiment;

[0063]FIG. 2 is a drawing which shows a method of manufacturing a firstsubstrate according to the first preferred embodiment;

[0064]FIG. 3 is a drawing which shows a method of manufacturing a secondsubstrate according to the first preferred embodiment;

[0065]FIG. 4 is a drawing which shows steps of manufacturing an opticaldisk according to the first preferred embodiment;

[0066]FIG. 5 is an appearance view of information which identifies anindividual according to the first preferred embodiment;

[0067]FIG. 6 is a drawing which shows a method of recording individualidentification information according to the first preferred embodiment;

[0068]FIG. 7 is a drawing which shows steps of manufacturing an opticaldisk according to a second preferred embodiment;

[0069]FIG. 8 is a cross sectional view of an optical recording mediumaccording to the second preferred embodiment which comprises three ormore information layers;

[0070]FIG. 9(a) is a drawing which shows an optical disk according to athird preferred embodiment, in which recorded in a BCA area 901 isinformation regarding a position at which individual identificationinformation 905 is recorded;

[0071]FIG. 9(b) is a drawing which shows an optical disk according tothe third preferred embodiment, in which recorded in a lead-in area 902is information regarding a position at which the individualidentification information 905 is recorded; and

[0072]FIG. 10 is a drawing which shows information for identifying anindividual according to the third preferred embodiment.

EXPLANATION OF THE REFERENCE SYMBOLS

[0073]101 first substrate

[0074]102 first information layer

[0075]103 intermediate layer

[0076]104 second information layer

[0077]105 second substrate

[0078]106 individual identification information

[0079]107 read-write light

[0080]108, 902 lead-in area

[0081]109, 204 data area

[0082]201 glass substrate

[0083]202 photoresist

[0084]203 metal plate

[0085]204, 301, 701 stamper

[0086]302, 402, 702 UV light hardening resin

[0087]303 thin film sheet

[0088]304, 403, 703 UV light

[0089]401 individual identification information recording beam

[0090]501 information recording area

[0091]502 holding hole

[0092]601 laser beam shaping optical system

[0093]602 motor

[0094]603 rotary encoder

[0095]604 intensity modulator

[0096]605 individual identification information signal generator

[0097]901 BCA area

[0098]902 learning area

[0099]1001 user data

[0100]1002 mark identifying an individual

BEST MODE FOR IMPLEMENTING THE INVENTION

[0101] Preferred embodiments of the present invention will now bedescribed with reference to associated drawings.

[0102] For ease of understanding, an explanation common to a firstthrough a third preferred embodiments will be given before describingthese preferred embodiments in detail.

[0103]FIG. 1 is a drawing of an optical recording medium, an opticaldisk in particular, according to the first and the second preferredembodiments. Shown in FIG. 1 is a particular example that there are onlytwo information layers.

[0104] The optical disk according to these comprises a first substrate101 in which convex and concave recording tracks are formed, a firstinformation layer 102 which is disposed to the first substrate on theside where the recording tracks are formed, an intermediate layer 103which is located between the first information layer 102 and a secondinformation layer 104 and is approximately transparent to read-writelight 107, the second information layer 104, and a second substrate 105which is approximately transparent to the read-write light 107.

[0105] The thickness of the second substrate 105 is about 0.1 mm so thataberration of the read-write light as it converges will be small and atolerance to the inclination of a disk surface will be large when arecording capacity is 20 GB or more and a reproducing head has NA of 0.7or more. The total thickness of the optical disk is about 1.2 mm,considering the rigidity of the disk and the compatibility with a CD orDVD. Hence, the thickness of the first substrate 101 is about 1.1 mm.

[0106] Reproduction is realized, as the read-write light 107 impingesupon a disk surface of the second substrate 105 side and converges atthe first information layer 102 or the second information layer 104 anda reflection intensity of thus reflected read-write light 107 isobserved. When recording is possible, recording is realized similarly toreproduction in a manner that the read-write light 107 is converged atthe first information layer 102 or the second information layer 104 andthe index of refraction of a first phase-change recording film or asecond phase-change recording film which forms the information layer ischanged.

[0107] Information 106 which identifies an individual is recorded in thelead-in area 108 or a BCA area (area located on the inner periphery sideto the lead-in area 108) which is present only in the first informationlayer 102 and does not include the convex and concave recording tracks.Recording of the information which identifies an individual is realizedas the phase and hence the index of refraction of a first layer-changerecording film or a second layer-change recording film are changed.These changes are irreversible and read-only.

[0108] The information 106 which identifies an individual (individualidentification information) corresponds to unique identificationinformation according to the present invention. Meanwhile, correspondingto a unique identification information recording area according to thepresent invention is a portion within the first information layer in theBCA area and the portion 108 within the first information layer in thelead-in area 102 according to the first and the second preferredembodiments.

[0109] The information layers may be formed by reflection films of goldor the like, in which case the information which identifies anindividual is recorded as the reflection films are dissolved andaccordingly removed. As the information which identifies an individualis recorded in one information layer out of the two information layers,recording which is optimal to the information layer which is to performrecording in is realized, and further, since there is no influence fromthe other one of these layers, it is possible to manufacture an opticaldisk which allows an improved reading accuracy.

[0110] In addition, as described later in relation to the thirdpreferred embodiment, information indicating the position of theinformation 106 which identifies an individual (information regardingthe position at which the unique identification information is recorded)may be recorded in the lead-in area 108 or the like which serves as aposition information recording area. In this case, the content of theinformation is the total number of the layers, the current layer, whichone of the layers contains the information which identifies anindividual, where a radial position or address of the recording ispositioned or the like, in addition to information which is necessaryfor ordinary reproduction. However, the present invention is applicableto even where there are not a plurality of layers. Since this allows tospecify a position to the information which identifies an individual, aneasy and quick access is possible.

[0111] Further, the information recorded in the BCA may not be thecontent of the information identifying an individual, but may beinformation which indicates the position at which the informationidentifying an individual is recorded. In short, information indicativeof the position is information such as a layer, an address, etc. Ifaddress information alone is used, the volume of data to be recorded isreduced, which in turn allows to reduce the area. An example that arecording area to identify an individual is a data area will bedescribed in detail in relation to the third preferred embodiment.

[0112] (First Preferred Embodiment)

[0113]FIG. 4 is a drawing which shows steps of manufacturing an opticaldisk according to the first preferred embodiment which comprises thefirst information layer 102 and the second information layer 104 forholding information so that by means of incident light, (1) theinformation will be reproduced or (2) the information will be recordedand reproduced, and comprises the BCA area disposed in the firstinformation layer 102 in which the individual identification information106 uniquely given to the optical disk is recorded.

[0114] First, methods of manufacturing the first substrate 101 and thesecond substrate 105 will be illustrated. A detailed description will beprovided later on recording of the information 106 (uniqueidentification information) identifying an individual in an opticalrecording medium manufacturing apparatus (FIG. 6) which comprises alaser 401, which is a characteristic according to the first preferredembodiment.

[0115]FIG. 2 is a drawing which shows a method of manufacturing thefirst substrate 101. A photoresist 202 is applied to a glass board 201(Step (2 a)) and exposed (Step (2 b)). After development (Step (2 c)),sputtering with Ni and plating with Ni are executed to form a metalplate 203 (Step (2 d)), and the metal plate 203 is peeled off (Step (2e)), whereby a stamper 204 is obtained. Using thus manufactured stamper204, by a method such as injection molding, the shape of the stamper 204is transferred onto a synthetic resin such as polycarbonate (Step (2 f))and the first substrate 101 is consequently obtained. Since the firstsubstrate 101 does not transmit the read-write light, the firstsubstrate 101 may be made of a substance such as glass and metal by the2P method or the like.

[0116] Next, FIG. 3 is a drawing which shows a method of manufacturingthe second substrate 105. Used as a stamper is a stamper which ismanufactured by a method similar to that shown with the steps forforming the first substrate. A UV light hardening resin 302 is appliedto a stamper 301 (Step (3 a)), and a thin film sheet 303, which is of asynthetic resin such as polycarbonate and has thickness of about 0.1 mm,is bonded to the top of this (Step (3 b)). After rotating the stamper301 and the thin film sheet 303 and removing an excessive portion of theUV light hardening resin such that the UV light hardening resin 302 willhave desired film thickness (Step (3 c)), UV light 304 is irradiated soas to harden the UV light hardening resin 302 (Step (3 d)) The interfacebetween the stamper 301 and the UV light hardening resin 302 isseparated, whereby the second substrate 105 is obtained (Step (3 e)).

[0117] Thus manufactured first substrate 101 and second substrate 105respectively have recording tracks which are reverse convex and concaveto those of the stampers. The convex and concave recording tracks areformed by pits or groove patterns which are in a spiral arrangement, andlocated within a range of an inner peripheral diameter of about 23 mm toan outer peripheral diameter of about 59 mm (Step (4 a)).

[0118] Meanwhile, in the case of a rewritable optical disk, over theconvex and concave recording tracks formed on the first substrate 101and the second substrate 105, the first information layer 102 and thesecond information layer 104 are respectively formed (Step (4 b), Step(4 e)). The information layers are formed by phase-change recordingfilms which are rewritable and held between dielectric films, andreflection films formed by metal thin films such as aluminum, silveralloy or the like is further disposed in accordance with necessity. Thedielectric films, the phase-change recording films and the reflectionfilms are formed by a sputtering method or the like. Since recording onand reproduction from the optical disk are from the second substrate 105side, as for the first information layer 102, the metal thin film, thedielectric film, the phase-change recording film and the dielectric filmare disposed in this order, and as for the second information layer 104,the dielectric film, the phase-change recording film and the dielectricfilm are disposed in this order. At this stage, the second informationlayer 104 in which the individual identification information is not tobe recorded is initially crystallized over the entire surface (However,such initial crystallization may be omitted during manufacturing of areproduction-only optical disk (ROM).)

[0119] In the case of a reproduction-only optical disk, for the purposeof reflecting the read-write light, a metal thin film of aluminum,silver alloy or the like is formed over the convex and concave recordingtracks which are formed on the first substrate 101 and the secondsubstrate 105. Meanwhile, in the case of a write-once-read-many opticaldisk, a dye recording film is formed over the convex and concaverecording tracks.

[0120] Next, the information 106 which identifies an individual isrecorded in the first information layer 102 (Step (4 c)). Theinformation is recorded as a stripe-like barcode, which has a lowreflection coefficient with respect to the read-write light and is anaggregation of diametrical parallel lines, is formed in an innerperipheral portion of the area in which there are the convex and concaverecording tracks, whereas the other area is subjected to initialcrystallization. The recorded area is however irreversible. Further, inthe case of a reproduction-only optical disk comprising only areflection film instead of a phase-change recording film, recording isrealized by a method which requires to dissolve and accordingly removethe reflection film.

[0121] After the recording in the first information layer 102, the firstsubstrate 101 and the second substrate 105 are bonded to each other(Step (4 f)). A UV light hardening resin 402 is applied onto the firstinformation layer 102, and the second substrate 105 is bonded such thatthe second information layer 104 will be faced with the firstinformation layer 102. Thus bonded substrate is rotated in such a mannerthat the UV light hardening resin 402 will have desired film thickness.The thickness is set to such thickness which will not be affectedbetween the information layers but cause minimum aberration of theread-write light. At last, UV light 403 is irradiated and the UV lighthardening resin 402 is accordingly hardened, thereby completing thedisk.

[0122] A method of recording the information which identifies anindividual will now be described in detail. FIG. 5 shows the appearanceof the individual identification information, and FIG. 6 shows a methodof recording the individual identification information. A hole 502 of adiameter of about 15 mm for holding an optical disk is formed in acentral portion, an information recording area 501 comprising the convexand concave recording tracks is formed within a radial range of about 23mm to about 59 mm. The information 106 which identifies an individual isrecorded between the information recording area 501 and the hole 502.The shape is a stripe-like barcode which has a low reflectioncoefficient with respect to the read-write light and is an aggregationof diametrical parallel lines, and the information is recorded as thewidths of the lines and the intervals between the lines are changed.

[0123] The laser 401 corresponds to unique identification informationrecording means according to the present invention.

[0124] In the case of a rewritable optical disk, the intensity of thelaser 401 is modulated by an intensity modulator 604 based on theinformation which identifies an individual which is generated by anindividual identification information signal generator 605, and thelaser 401 whose intensity is modulated is irradiated upon thephase-change recording film which forms the first information layer 102while rotating the first substrate 101 with a motor 602. Thephase-change recording film irradiated with the laser 401 accordinglyhas a crystal phase which exhibits a high reflection coefficient withrespect to the read-write light, whereas the phase-change recording filmnot irradiated with the laser 401 remains in an amorphous phase whichhas a low reflection coefficient. The portions not irradiated with thelaser 401 serve as lines having low reflection coefficients, whereby arecording pattern is created. In reality, recording is realized with arecording power remaining at 0.5 W through 2.0 W and the irradiationbeam shaped by a laser beam shaping optical system 601 as a long andnarrow shape elongated along the radial direction of the substrate,e.g., a shape which is 100 μm×1 μm. Thus shaped laser is irradiatedwhile cyclically shifting the laser in the radial direction, so that apattern like a barcode having any desired lengths and intervals isobtained.

[0125] If the same laser is used as the laser for recording theinformation which identifies an individual and the laser for initiallycrystallizing the phase-change recording film, the steps (4 c), (4 e)and the like are simplified (However, such initial crystallization maybe omitted during manufacturing of a reproduction-only optical disk(ROM).)

[0126] Further, although the foregoing has described the recording inthe BCA by means of a change in phase condition, the recording may beattained in the BCA by feeding a strong recording power and dissolvingthe phase-change recording film.

[0127] A reproduction-only optical disk does not comprise thephase-change recording film but comprises only the metal thin film.Hence, the information which identifies an individual is provided, withthe metal thin film dissolved and accordingly removed using ahigh-output laser such as a YAG laser. More specifically, the laser beamshaping optical system 601 shapes the laser 401 into a shape of about 10μm×about 1.2 mm, and after the intensity of the laser 401 is modulatedby the intensity modulator 604 based on the information which identifiesan individual, the laser 401 is irradiated upon the metal thin film. Themetal thin film irradiated with the laser 401 is dissolved and removeddue to the generated heat, and accordingly exhibits a low reflectioncoefficient. In this manner, a recording pattern is formed as lineswhose reflection coefficients are low.

[0128] The information which identifies an individual may be recorded bymeans of tracking servo over the irregular topography. This makes itpossible to record at an accurate position.

[0129] In the case of a write-once-read-many optical disk, a laser whosewavelength is close to that of the read-write light is shaped in asimilar manner to that for a rewritable optical disk, and irradiatedupon the dye recording film which forms the information layer. Thereflection coefficient becomes low in portions irradiated with thelaser, whereby the recording pattern is created.

[0130] The method described above according to the first preferredembodiment which demands to record postscript information in one of thesubstrates and bond the substrates to each other is close to aconventional method which is used for a DVD. Since this requires only asmall number of modifications, easy manufacturing is possible.

[0131] The identification information 106 which identifies an individualmay be recorded in the second information layer 104. Recording in thefirst information layer 102 has an advantage that handling is easy sincethe first information layer 102 is located on the first substrate 101which is the thickest, whereas recording in the second information layer104 has an advantage that since the second information layer 104 iscloser to the incident surface of the read-write light than the firstinformation layer 102 is, the read-write light 107 is led to a focusquickly and detection of the information is therefore easy.

[0132] (Second Preferred Embodiment)

[0133]FIG. 7 is a drawing which shows steps of manufacturing an opticaldisk according to the second preferred embodiment The first substrate101 is comprised of a synthetic resin such as polycarbonate, glass ormetal, and formed by an injection molding method, the 2P method or thelike using a stamper which is manufactured in a similar manner to thatused in the first preferred embodiment (Step (7 a)). The firstinformation layer 102 is comprised of a reflection film formed by ametal thin film of aluminum or the like and a phase-change recordingfilm which is rewritable and held between dielectric films, and isformed by sputtering or otherwise disposing the metal thin film, thedielectric film, the phase-change recording film and the dielectric filmin this order (Step (7 b)).

[0134] After forming the first information layer 102, the information106 which identifies an individual is recorded (Step (7 c)). A method ofrecording is similar to that used in the first preferred embodiment. Inaddition, at this stage, the phase-change recording film of the firstinformation layer 102 is initially crystallized in an area except forthose portions in which the individual identification information 106 isrecorded.

[0135] Following this, a UV light hardening resin 702 is applied on thefirst information layer 102 and a stamper 701 is placed on this (Step (7d)), and the substrate 101 and the stamper 701, which are bonded to eachother such that the UV light hardening resin 702 has desired thickness,are rotated. UV light 703 is irradiated upon the UV light hardeningresin 702 and the UV light hardening resin 702 is accordingly hardened(Step (7 e)), and the stamper 701 is separated from the UV lighthardening resin 702 (Step (7 f)). The convex and concave recordingtracks on the stamper 701 are thus transferred onto the UV lighthardening resin 702.

[0136] Next, the second information layer 104 is formed on the UV lighthardening resin 702 (Step (7 g)). Like the first information layer 102,the second information layer 104 comprises a rewritable phase-changerecording film which is held between dielectric films, and further, areflection film formed by a metal thin film of silver alloy or the likeif necessary, and is formed by sputtering or otherwise disposing thedielectric film, the phase-change recording film and the dielectric filmin this order. The phase-change recording film of the second informationlayer 104 is initially crystallized at this stage.

[0137] At last, the UV light hardening resin 702 is applied onto thesecond information layer 104 and the second substrate 105 is bonded tothis (Step (7 h)), and this is rotated such that the UV light hardeningresin 702 will have desired thickness, and after this, UV light isirradiated, the UV light hardening resin 702 is hardened and the disk iscompleted (Step (7 i)).

[0138] Alternatively, the second phase-change recording film may beinitially crystallized and the information 106 which identifies anindividual may be recorded after forming the second information layer104. In this case, the first phase-change recording film is initiallycrystallized over the entire surface in advance. With the identificationinformation 106 which identifies an individual recorded in the secondinformation layer 104 which is closer to the incident surface of theread-write light, fast leading to a focus is realized, and therefore,detection of the information is quick and easy.

[0139] It is possible to manufacture an optical disk which comprisesthree or more information layers with the manufacturing method accordingto the second preferred embodiment, and when an optical disk whichcomprises three or more information layers is to be fabricated, the diskis manufactured by returning to the step (7 d) from the step (7 g) andrepeating the step (7 d) through the step (7 g) over a necessary numberof times. During this, the information which identifies an individualmay be provided prior to the bonding step (7 h) instead of providing theinformation which identifies an individual at the step (7 c). (FIG. 8shows an optical recording medium which comprises four informationlayers, in which the information identifying an individual is recordedin the information layer which is the closest to the incident surface ofthe read-write light.)

[0140] Of course, the information 106 identifying an individual may berecorded in the first information layer 102 and the second informationlayer 104 but at positions which do not overlap with each other asviewed from the read-write light. In this case, although the sequenceproceeds to the step (7 h) via the step (7 c) from the step (7 g), sincean individual identification information recording beam emitted from thelaser 401 is modified for each layer and recording positions in therespective information layers are changed, it is possible to reproducewithout an influence of other layers during reproduction. This makes itpossible to manufacture an optical recording medium which comprises aplurality of information layers for holding information so that by meansof incident light, (7 g) (1) information will be reproduced or (2)information will be recorded and reproduced, wherein there are uniqueidentification information recording areas, in which the uniqueidentification information uniquely given to the optical recordingmedium is recorded, disposed in two or more of the plurality ofinformation layers so as not to overlap with each other as viewed from adirection of the incident light.

[0141] This is applicable to an optical recording medium of other shapeswhich are not limited only to a disk-like shape but include a card-likeshape.

[0142] (Third Preferred Embodiment)

[0143] FIGS. 9(a) and 9(b) are drawings of an optical disk according tothe third preferred embodiment which comprises an information layer forholding information so that by means of incident light, (1) informationwill be reproduced or (2) information will be recorded and reproduced,wherein there is a predetermined position information recording area inwhich information regarding a position at which the individualidentification information 905, which is given uniquely to the opticaldisk is recorded, is recorded.

[0144] The position information recording area according to the presentinvention corresponds to a BCA area 901 in the optical disk shown inFIG. 9(a) but to a lead-in area 902 in the optical disk shown in FIG.9(b).

[0145] The optical disk shown in FIG. 9(a) is divided into the BCA area901, the lead-in area 902, a learning area 903 and a data area 904, butinto the lead-in area 902, the learning area 903 and the data area 904in the optical disk shown in FIG. 9(b). Although the BCA area 901 andthe learning area 903 are disposed separately in these examples, the BCAarea 901 and the learning area 903 may be disposed as one integratedarea instead of particularly separating the two.

[0146] The lead-in area 902 contains data which are constituted bypre-pits. Since the pre-pits are created while a molding board foroptical disks is manufactured, the pre-pits are data common to alloptical disks which are made from one molding board for optical disks.The content of the data is the number assigned to the molding board foroptical disks, an optimal intensity value of the laser light to read thedata recorded on the optical disks, etc.

[0147] Recording in the BCA area 901 is realized utilizing a physical oroptical irreversible reaction. A detailed recording method is asdescribed in relation to the first preferred embodiment. However, inorder to obtain a desired pattern, the laser needs be shaped into a beamdifferently.

[0148] The learning area 903 is an area in which the intensity of thelaser light for recording or reproduction is adjusted or learned whileirradiating the laser light upon this area with an optical disk set inan optical disk apparatus. The data area 904 is an area for recording orreproducing ordinary data.

[0149] In the third preferred embodiment, the information (e.g., layers,addresses) expressing a recording position of the informationidentifying an individual is recorded in the BCA area 901 in the case ofthe optical disk shown in 9 a but in the lead-in area 902 in the case ofthe optical disk shown in 9 b. The individual identification information905 itself for an actual individual is recorded, by means of a laser, inthe data area 904 which is an area other than the BCA area 901, thelead-in area 902 and the like. (The individual identificationinformation 905 may be recorded in a control area for example which isfor recording control data.)

[0150] The laser corresponds to means which includes the uniqueidentification information recording means and the position informationrecording means.

[0151] For recording or reproduction, an operation is performed in whichthe information in the BCA area 901 or in the lead-in area 902 is read,and after confirming the recording position of the individualidentification information 905, the individual identificationinformation is confirmed. With the two stages of confirmation of theindividual identification information incorporated in this manner, it ispossible to dramatically improve a capability of preventing unauthorizedcopying and bootleg editions.

[0152]FIG. 10 shows one example of the information identifying anindividual which is recorded in the actual data area 904. The records ofthe individual identification information 905 for identifying anindividual are along the recording tracks which, partially or as theyinclude the lengths, the intervals, the radial positions, the addresspositions and the layer positions, express 0 or 1. The lengths asdescribed herein do not merely denote the lengths along the peripherydirection but also the lengths in the radial direction, i.e., the sizes.

[0153] In addition, the illustrated example is the record across fivetracks, and the information identifying an individual may be over awidth corresponding to one track or more in this manner. When the widthis across one track alone, there is an advantage that only a small rangeof error correction is needed during reproduction of user data 1001. Atthis stage, the information identifying an individual may be recordedunder tracking servo. This permits to record at accurate positions.

[0154] Marks 1002 for identifying an individual to be recorded havelengths which enable error correction (which are equal to or shorterthan a maximum length which enables error correction). Hence, even whenthe marks 1002 are recorded in the data area, since error correction ispossible during reproduction, the content of the original user data 1001will not become impossible to read. This eliminates the necessity ofdisposing the inner peripheral area. As a result, the data area isexpanded in area size, which in turn allows to increase the storagecapacity. This is more effective, as disks are smaller in diameter.Further, this can be regarded as a very large effect, since a limitedarea is utilized effectively.

[0155] In addition, the individual identification information may berecorded in the lead-in area 902 or an lead-out which is located at theouter-most periphery, instead of recording in the data area 904. Asimilar effect is obtainable, even with the recording in the lead-inarea 902 or the lead-out area.

[0156] The first through the third preferred embodiments have beendescribed in detail above.

[0157] As the foregoing has described, with respect to the opticalrecording medium or the method of manufacturing an optical recordingmedium according to the present invention, in the optical recordingmedium comprising the plurality of information layers, as theinformation identifying an individual is additionally recorded in one ofthe information layers, the individual identification information isrecorded in that information layer in an optimal fashion withoutinfluenced by the other information layers, and hence, theidentification information can be read out accurately.

[0158] Further, with the identification information recorded in theinformation layer which is the closest to the incident surface of theread-write light, the information identifying an individual can detectedeasily and quickly.

[0159] Further, in the event that the position of the identificationinformation is recorded instead of recording the identificationinformation itself, the recording area may be reduced while maintainingthe compatibility with a DVD.

[0160] Further, if the optical disk comprises a plurality of substrates,with the information identifying an individual recorded in theinformation layer which is in the thickest one of the substrates,handling and manufacturing are easy.

[0161] Further, in the event that the information identifying anindividual is recorded in at least two information layers in such amanner that the respective pieces of the identification information arenot at recording positions which overlap with each other as viewed fromthe read-write light, it is possible to read the identificationinformation accurately during reproduction without affected by the otherlayers.

[0162] Further, with the position of the information identifying anindividual (layers, addresses, etc.) recorded in the lead-in area, it ispossible to quickly and easily read the information identifying anindividual.

[0163] Further, if the information identifying an individual is recordedin the data area, it is possible to expand the data area, and therefore,increase the storage capacity.

[0164] Further, if the information identifying an individual is over onetrack, it is possible to reduce the recording area of the informationidentifying an individual, and hence, increase the data area.

[0165] In addition, the present invention is directed also to a programwhich works with a computer and makes the computer execute the functionsof all or some of the means (or apparatuses, elements, circuits,portions, etc.) of the optical recording medium manufacturing apparatusaccording to the present invention described above. Of course, computersare not limited to pure hardware such as a CPU but may include firmware,OS and further peripheral equipment.

[0166] The present invention is directed also to a program which workswith a computer and makes the computer perform the operations at all orsome steps (or processes, operations, effects, etc.) of the opticalrecording medium manufacturing method according to the present inventiondescribed above.

[0167] Some of the means (or apparatuses, elements, circuits, portions,etc.) according to the present invention and some of the steps (orprocesses, operations, effects, etc.) according to the present inventionrefers to some of the means or steps among these plurality of means orsteps, or some functions or some operations in one means or at one step.

[0168] Some of the apparatuses (or elements, circuits, portions, etc.)according to the present invention refers to some of the apparatusesamong these plurality of apparatuses, or some of the means (or elements,circuits, portions, etc.) in one of the apparatuses, or some functionsin one of the means.

[0169] Also covered by the present invention is a recording medium inwhich the program according to the present invention is recorded andwhich can be read on a computer. With respect to use of the programaccording to the present invention, the program maybe recorded in arecording medium which can be read on a computer and the program maywork with the computer. Further, with respect to use of the programaccording to the present invention, the program may be transmitted in atransmission medium, read on a computer and work with the computer. Therecording medium includes a ROM or the like, the transmission mediumincludes a transmission medium such as the Internet, light, an electricwave, a sound wave and the like.

[0170] The structure according to the present invention may be realizedby software or software.

[0171] Further, the present invention is directed also to a medium whichholds a program which makes a computer execute all or some functions ofall or some means of the optical recording medium manufacturingapparatus according to the present invention described above, in such amanner that as the program which can be read on a computer is read, theprogram works with the computer to execute these functions.

[0172] The present invention is directed also to a medium which holds aprogram which makes a computer perform all or some operations at all orsome steps of the optical recording medium manufacturing methodaccording to the present invention described above, in such a mannerthat as the program which can be read on a computer is read, the programworks with the computer to perform these operations.

INDUSTRIAL USE

[0173] As clearly described above, the present invention is advantageousin that an improved accuracy is realized for reading unique informationidentifying an individual from an optical disk which comprises aplurality of information layers.

[0174] In addition, the present invention is advantageous in that it ispossible to reduce a dedicated area for recording unique informationidentifying an individual.

1. An optical recording medium which comprises a plurality ofinformation layers for holding information so that by means of incidentlight, (1) said information will be reproduced or (2) said informationwill be recorded and reproduced, comprising a unique identificationinformation recording area in which unique identification informationuniquely given to said optical recording medium is recorded and which isdisposed in one of said plurality of information layers.
 2. The opticalrecording medium of claim 1, wherein said unique identificationinformation recording area is disposed in the information layer amongsaid plurality of information layers which is the closest to a surfaceupon which said light is incident.
 3. The optical recording medium ofclaim 1, wherein said plurality of information layers are formed onpredetermined substrates, and said unique identification informationrecording area is disposed in the information layer among said pluralityof information layers which is formed on the thickest one of saidsubstrates.
 4. An optical recording medium which comprises a pluralityof information layers for holding information so that by means ofincident light, (1) said information will be reproduced or (2) saidinformation will be recorded and reproduced, comprising uniqueidentification information recording areas in which uniqueidentification information uniquely given to said optical recordingmedium is recorded and which are disposed in two or more of saidplurality of information layers so as not to overlap with each other asviewed from a direction in which said light is incident.
 5. The opticalrecording medium of claim 1 or 4, wherein said plurality of informationlayers are formed on a substrate which has the shape of a disk, and saidunique identification information is recorded in the form of stripeswhich are along the radial direction of said disk.
 6. The opticalrecording medium of claim 1 or 4, wherein said plurality of informationlayers are formed mainly by thin films which can assume two states whichare irreversible and can be detected when irradiated with a laser. 7.The optical recording medium of claim 1 or 4, wherein said plurality ofinformation layers are formed mainly by thin films which can bedissolved and accordingly removed by irradiation of light.
 8. An opticaldisk which comprises an information layer for holding information sothat by means of incident light, (1) information will be reproduced or(2) information will be recorded and reproduced, comprising apredetermined position information recording area in which informationregarding a position at which unique identification information, whichis given uniquely to said optical disk is recorded, is recorded.
 9. Theoptical recording medium of claim 8, wherein said position informationrecording area is a BCA area or lead-in area which is used forreproduction of said information.
 10. The optical recording medium ofclaim 8, wherein said unique identification information is recorded in adata area in which said information is recorded or which is used torecord said information.
 11. The optical recording medium of claim 10,wherein said unique identification information is recorded so as to havea length which permits error correction during reproduction of saidinformation.
 12. The optical recording medium of claim 10, wherein saidinformation layer is formed on a substrate which comprises a pluralityof recording tracks and has the shape of a disk, wherein said uniqueidentification information is recorded so as to have a width which isnot beyond one of said recording tracks.
 13. An optical recording mediummanufacturing method of manufacturing an optical recording mediumcomprising a plurality of information layers for holding information sothat by means of incident light, (1) said information will be reproducedor (2) said information will be recorded and reproduced, comprising astep of forming a unique identification information recording area inone of said plurality of information layers, and recording uniqueidentification information, which is given uniquely to said opticaldisk, in said unique identification information recording area.
 14. Anoptical recording medium manufacturing method of manufacturing anoptical recording medium comprising a plurality of information layersfor holding information so that by means of incident light, (1) saidinformation will be reproduced or (2) said information will be recordedand reproduced, comprising a step of forming unique identificationinformation recording areas in two or more of said plurality ofinformation layers so as not to overlap with each other as viewed from adirection in which said light is incident, and recording uniqueidentification information, which is given uniquely to said opticaldisk, in said unique identification information recording areas.
 15. Anoptical recording medium manufacturing method of manufacturing anoptical recording medium comprising an information layer for holdinginformation so that by means of incident light, (1) information will bereproduced or (2) information will be recorded and reproduced,comprising: a step of recording unique identification information whichis given uniquely to said optical recording medium; and a step offorming a predetermined position information recording area andrecording, in said position information recording area, informationregarding a position at which said unique identification information isrecorded.
 16. The optical recording medium manufacturing method of anyone of claims 13 through 15, wherein said information layer is formedmainly by a phase-change recording film, and said unique identificationinformation is recorded utilizing a modulated intensity of laser lightwhich is for initially crystallizing said phase-change recording film.17. The optical recording medium manufacturing method of any one ofclaims 13 through 15, wherein said information layer is formed mainly bya reflection film against said light which is indecent, and said uniqueidentification information is recorded utilizing dissolution andconsequent removal of said reflection film.
 18. An optical recordingmedium manufacturing apparatus of manufacturing an optical recordingmedium comprising a plurality of information layers for holdinginformation so that by means of incident light, (1) said informationwill be reproduced or (2) said information will be recorded andreproduced, comprising unique identification information recording meanswhich records unique identification information, which is given uniquelyto said optical recording medium, in a unique identification informationrecording area which is formed in one of said plurality of informationlayers.
 19. An optical recording medium manufacturing apparatus ofmanufacturing an optical recording medium comprising a plurality ofinformation layers for holding information so that by means of incidentlight, (1) said information will be reproduced or (2) said informationwill be recorded and reproduced, comprising unique identificationinformation recording means which records unique identificationinformation, which is given uniquely to said optical recording medium,in unique identification information recording areas which are formed intwo or more of said plurality of information layers so as not to overlapwith each other as viewed from a direction in which said light isincident.
 20. An optical recording medium manufacturing apparatus ofmanufacturing an optical recording medium comprising an informationlayer for holding information so that by means of incident light, (1)said information will be reproduced or (2) said information will berecorded and reproduced, comprising: unique identification informationrecording means which records unique identification information which isgiven uniquely to said optical recording medium; and positioninformation recording means which records, in a predetermined positioninformation recording area, information regarding a position at whichsaid unique identification information is recorded.
 21. The opticalrecording medium manufacturing apparatus of any one of claims 18 through20, wherein said information layers are formed on a substrate whichcomprises a plurality of recording tracks and has the shape of a disk,and said unique identification information recording means records saidunique identification information, 53 utilizing tracking servo over saidtracking tracks.
 22. A program which makes a computer execute the stepin the optical recording medium manufacturing method of claim 13 offorming said unique identification information recording area in one ofsaid plurality of information layers and recording said uniqueidentification information in said unique identification informationrecording area.
 23. A medium which can be processed on a computer andholds a program which makes a computer execute the step in the opticalrecording medium manufacturing method of claim 13 of forming said uniqueidentification information recording area in one of said plurality ofinformation layers and recording said unique identification informationin said unique identification information recording area.
 24. A programwhich makes a computer execute the step in the optical recording mediummanufacturing method of claim 14 of forming said unique identificationinformation recording areas in two or more of said plurality ofinformation layers so as not to overlap with each other as viewed fromthe direction in which said light is incident, and recording said uniqueidentification information, which is given uniquely to said opticaldisk, in said unique identification information recording areas.
 25. Amedium which can be processed on a computer and holds a program whichmakes a computer execute the step in the optical recording mediummanufacturing method of claim 14 of forming said unique identificationinformation recording areas in two or more of said plurality ofinformation layers so as not to overlap with each other as viewed fromthe direction in which said light is incident, and recording said uniqueidentification information, which is given uniquely to said opticaldisk, in said unique identification information recording areas.
 26. Aprogram which makes a computer execute all or some of the step in theoptical recording medium manufacturing method of claim 15 of recordingsaid unique identification information which is given uniquely to saidoptical recording medium, and the step in the optical recording mediummanufacturing method of claim 15 of forming said predetermined positioninformation recording area and recording, in said position informationrecording area, the information regarding the position at which saidunique identification information is recorded.
 27. A medium which can beprocessed on a computer and holds a program which makes a computerexecute all or some of the step in the optical recording mediummanufacturing method of claim 15 of recording said unique identificationinformation which is given uniquely to said optical recording medium,and the step in the optical recording medium manufacturing method ofclaim 15 of forming said predetermined position information recordingarea and recording, in said position information recording area, theinformation regarding the position at which said unique identificationinformation is recorded.